| 摘要 |
The present invention is a pre-aligner capable of determining the center of a wafer by casting light onto a wafer that is positioned above a charge-coupled device (CCD). The pre-aligner perfoi ns this operation by directing light emitted from a single LED simultaneously onto the wafer and the CCD. The light emitted from the LED is directed through a light guide in order to direct the light onto the wafer and CCD. A lens collimates the light exiting the light guide such that the light, as it passes the wafer's edge, is substantially perpendicular to the wafer's edge. The light guide may be removably secured to the pre-aligner housing for easy installation removal. The prealigner is capable of self-calibrate the LED. |
